(i) Technical Field
The present invention relates to a piston drive device.
(ii) Related Art
There is known a device in which plural pistons are connected to a rotational shaft and reciprocate. Japanese Patent Application Publication No. 2008-95700 discloses a related device.
For example, in a case where plural compression pistons and plural vacuum pistons different from each other in a diameter of a piston head are connected to the rotational shaft, the piston drive device might increase its size in the axial direction of the rotational shaft, depending on the order in which the compression pistons and the vacuum pistons are arranged.